Apparatus, medium, and method for correcting color of an image

ABSTRACT

An apparatus, medium, and method for correcting color of an image. The apparatus may includes a user interface which displays each of N reference patches, removes non-gray components from the displayed N reference patches, according to the characteristics of a user&#39;s visual system, and outputs the reference patches from which the non-gray components have been removed as adjusted reference patches, a table generator which generates at least one lookup table that has, as addresses, color component values for a current image and stores color component values of the adjusted reference patches as data, and a color corrector which addresses the at least one lookup table using the color component values of the image to read data corresponding to correction information for the color component values of the image and outputs the read data as the result of the correcting of color of the image.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Korean Patent Application No.10-2004-0021818, filed on Mar. 30, 2004, in the Korean IntellectualProperty Office, the disclosure of which is incorporated herein in itsentirety by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

Embodiments of the present invention relate to an image displayapparatus, medium, and method for displaying an image, and moreparticularly, to an apparatus, medium, method for correcting color of animage.

2. Description of the Related Art

In general, when the gamma characteristics of red (R), green (G), andblue (B) channels are the same in an image display device, graycomponents of an image to be displayed via the image display device donot include non-gray components. However, in most image display devices,each of the gamma characteristics of R, G, and B channels are notidentical. Thus, gray components of an image to be displayed includenon-gray components. Accordingly, in a conventional color-correctingmethod, the color reproduction characteristics of an image displaydevice are found by using a colorimetric apparatus, and then non-graycomponents are removed from gray components of an image using the colorreproduction characteristics.

Consequently, the conventional color-correcting method has adisadvantage in that a user of an image display device cannot correctthe gray color reproduction characteristics of the image display devicewithout a high-priced calorimetric apparatus.

SUMMARY OF THE INVENTION

Embodiments of the present invention include an image color-correctingapparatus, medium, and method for adjusting the characteristics of animage display device using only the characteristics of a user's visualsystem to correct color of an image using the adjusted characteristicsof the image display device.

To achieve the above and/or other aspects and advantages, embodiments ofthe present invention set forth an apparatus for correcting color of animage, the apparatus including a user interface to display each of Nreference patches, with N being a number greater than or equal to 1, toremove a non-gray component from a displayed reference patch based onuser interaction and according to characteristics of the user's visualsystem, as an adjusted reference patch, and to output the adjustedreference patch, a table generator to generate at least one tableincluding color component values, as addresses, and storing colorcomponent values of the adjusted reference patch as data in the at leastone table, and a color corrector to address the at least one table,using color component values of the image, to read data corresponding tothe color component values of the image and output the read data for acolor corrected image.

The user interface may include a luminance manipulator to be manipulatedby the user to match a luminance of the displayed reference patch with aluminance of a paired displayed background, a color componentmanipulator to be manipulated by the user to remove the non-graycomponent from the displayed reference patch, and an adjusted referencepatch generator to generate the adjusted reference patch for thedisplayed reference patch based on the luminance manipulation and thecolor component manipulation.

The color component manipulator may include a gray balance guide map torepresent designators of a plurality of chroma components in differentlocations on a two-dimensional space, and gray balance cursors providedwithin the displayed reference patch and the gray balance guide map andto be manipulated by the user so as to move the gray balance cursorstogether an identical distance in an identical direction, wherein, as agray balance cursor within the gray balance guide map gets closer to anarbitrary designator, a chroma component associated with the arbitrarydesignator is correspondingly removed from the displayed referencepatch. A pattern of the gray balance cursors within the reference patchmay also be identical to a pattern of the displayed background.

The user interface may display a plurality of paired reference patchesand backgrounds, pair by pair, removes non-gray components from thedisplayed reference patches, according to the characteristics of theuser's visual system, matches luminances of the displayed referencepatches with luminances of displayed backgrounds, according to thecharacteristics of the user's visual system, as adjusted referencespatches, respectively, and outputs the adjusted reference patches,wherein each of the plurality of pairs includes one predeterminedreference patch paired with one predetermined background.

In addition, the displayed background may have a pattern in which atleast two of black, white, and gray lines oppose each other. Further, inthe displayed background, a number of adjacent lines with a same colormay be less than 3 lines.

The table generator may include a gamma matcher to match the luminancesof N backgrounds, with color component values the image may have, usinga gamma function, and a color component matcher to analyze the gammamatcher matching results, match the color components values the imagemay have with the color component values of the adjusted referencepatches, and output the color component value matching results as atleast one table.

The color corrector may include a table reader to address the at leastone table, using the color component values of the image, to read thedata corresponding to the color component values of the image and outputthe read data for the color corrected image, and a data generator to,when the at least one table does not include data corresponding to thecolor component values of the image, predict data corresponding to thecolor component values using piecewise linear modeling using data fromthe at least one table, and output results of the prediction for thecolor corrected image.

To achieve the above and/or other aspects and advantages, embodiments ofthe present invention set forth a method of correcting color of animage, including displaying each of N, with N being a number greaterthan or equal to 1, reference patches, removing a non-gray componentfrom a reference patch, according to an interaction by a user andcharacteristics of the user's visual system, and determining thenon-gray component removed reference patch as an adjusted referencepatch, generating at least one table that has, as addresses, colorcomponent values and stores color component values of the adjustedreference patch as data in the at least one table, and addressing the atleast one table, using color component values of the image, to read datacorresponding to the color component values of the image and outputtingthe read data for a color corrected image.

A plurality of pairs of reference patches and backgrounds may bedisplayed, pair by pair, non-gray components are removed from thedisplayed reference patches, according to the characteristics of theuser's visual system, luminances of the displayed reference patchesmatch with luminances of the displayed backgrounds, according to thecharacteristics of the user's visual system, as the adjusted referencepatches, wherein each of the plurality of pairs includes onepredetermined reference patch paired with one predetermined background.

In addition, the outputting of the adjusted reference patches mayinclude initializing a variable n, displaying a paired nth referencepatch and an nth background, together, removing a non-gray componentfrom the displayed nth reference patch, according to the characteristicsof the user's visual system, determining whether the variable n is equalto N and if it is determined that the variable n is equal to Nproceeding to the generating of the at least lookup table, and if it isdetermined that the variable n is not equal to N increasing the variablen by 1 and proceeding to the displaying of the nth reference patch andthe nth background.

Further, the outputting of the adjusted reference patches may includematching a luminance of the nth reference patch with a luminance of thenth background, according to the characteristics of the user's visualsystem.

To achieve the above and/or other aspects and advantages, embodiments ofthe present invention set forth a medium including computer readablecode implementing embodiments of the present invention.

Additional aspects and/or advantages of the invention will be set forthin part in the description which follows and, in part, will be obviousfrom the description, or may be learned by practice of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects and advantages of the invention will becomeapparent and more readily appreciated from the following description ofthe embodiments, taken in conjunction with the accompanying drawings ofwhich:

FIG. 1 is a block diagram of an apparatus correcting color of an image,according to an embodiment of the present invention;

FIG. 2 is a block diagram of a user interface of FIG. 1, according to anembodiment of the present invention;

FIG. 3 illustrates a user interface for FIG. 1, according to anembodiment of the present invention;

FIG. 4 illustrates examples of backgrounds;

FIG. 5 is a block diagram of a table generator for FIG. 1, according toan embodiment of the present invention;

FIG. 6 is a block diagram of a color corrector of FIG. 1, according toan embodiment of the present invention;

FIG. 7 is an exemplary graph for a first lookup table;

FIG. 8 is a flowchart explaining a method of correcting color of animage, according to an embodiment of the present invention; and

FIG. 9 is a flowchart explaining operation 300 of FIG. 8, according toan embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the embodiments of the presentinvention, examples of which are illustrated in the accompanyingdrawings, wherein like reference numerals refer to the like elementsthroughout. The embodiments are described below to explain the presentinvention by referring to the figures.

FIG. 1 is a block diagram of an apparatus correcting the color of animage, according to an embodiment of the present invention. Referring toFIG. 1, the apparatus may include a user interface 10, a table generator12, and a color corrector 14.

The apparatus of FIG. 1 corrects the color of an image displayed on animage display device as follows. Here, the image display device refersto a monitor or the like, for example.

According to an embodiment of the present invention, the user interface10 can display each of N reference patches on the image display device,remove non-gray components from the displayed reference patches,according to the characteristics of a user's visual system, that is userinteraction, and output the reference patches from which the non-graycomponents have been removed as adjusted reference patches to the tablegenerator 12. Here, N can be a predetermined positive number greaterthan or equal to “1”, where the greater the predetermined positivenumber, the better, according to an embodiment of the present invention.

According to another embodiment of the present invention, the userinterface 10 can display a plurality of pairs of reference patches andbackgrounds, one by one. Each background paired with each referencepatch can be pre-determined. For example, luminances LB and LP of apaired background and reference patch may have the followingrelationship of Equation 1:

$\begin{matrix}{{L_{B} = \frac{L_{P}}{B}},} & (1)\end{matrix}$wherein L_(B) can be represented by a percentage and B denotes a maximumnumber of levels of an electric signal used to generate thecorresponding different luminance levels, and which may be available foreach pixel displayed on the image display device, for example, B may be255.

The user interface 10 permits a user to remove non-gray components fromthe reference patches of the displayed pairs, according to thecharacteristics of the user's visual system, i.e., based on the user'sviewed perception, and permits a user to match luminances of thedisplayed reference patches with luminances of the displayedbackgrounds, also according to the characteristics of the user's visualsystem. Here, the user interface 10 outputs the reference patches, fromwhich the non-gray components have been removed and the luminances havebeen matched with the luminances of the displayed backgrounds, asadjusted reference patches.

The table generator 12 generates at least one lookup table (LUT) whichstores, as addresses, color component values an image may have and asdata color component values of the adjusted reference patches, andoutputs the generated at least one LUT to the color corrector 14. Here,the color component values may refer to R, G, and B component values.Also, the LUTs for storing the R, G, and B component values,respectively, may be generated separately. For example, the LUT for theR component stores, as addresses, R component values the image may haveand R component values of the adjusted reference patches as data.

The color corrector 14 addresses at least one LUT using color componentvalues of an image to be displayed, input via an input node IN1, readsdata corresponding to color component values from the at least one LUT,and outputs the read data as the result of a corrected color of theimage to be displayed via an output node OUT1.

FIG. 2 is a block diagram of the user interface 10 of FIG. 1, accordingto an embodiment of the present invention. Referring to FIG. 2, a userinterface 10A may include a luminance manipulator 32, a chroma componentmanipulator 34, and an adjusted reference patch generator 36.

The luminance manipulator 32 is manipulated by a user to match theluminances of the displayed reference patches with the luminances of thedisplayed backgrounds, paired with the displayed reference patches, andoutputs the manipulation results to the adjusted reference patchgenerator 36. In other words, the user manipulates the luminancemanipulator 32 to match the luminances of the displayed referencepatches with the luminances of the displayed backgrounds according tothe characteristics of the user's visual system.

The chroma component manipulator 34 is manipulated by a user to removethe non-gray components from the displayed reference patches, andoutputs the removal results to the adjusted reference patch generator36. In other words, the user manipulates the chroma componentmanipulator 34 to remove the non-gray components from the displayedreference patches according to the characteristics of the user's visualsystem.

The adjusted reference patch generator 36 generates the adjustedreference patches using the reference patches, the luminances of whichhave been manipulated by the luminance manipulator 32 and from which thenon-gray components have been removed by the chroma componentmanipulator 34, and outputs the adjusted reference patches to the colorcorrector 14 via an output node OUT2.

FIG. 3 is a view illustrating the user interface 10 of FIG. 1, accordingto an embodiment of the present invention. The user interface 10includes a reference patch 50, a background 52, gray balance cursors 54and 58, a gray balance guide map 56, a group of reference patches 60, agroup of adjusted reference patches 62, and a luminance manipulatingportion 64 having a slide bar 66.

For example, when N=7, as shown in FIG. 3, the group of referencepatches 60 includes seven reference patches 80 through 92, and the groupof adjusted reference patches 62 includes seven adjusted referencepatches 100 through 112.

The gray balance guide map 56 and the gray balance cursors 54 and 58correspond to the chroma component manipulator 34 of FIG. 2. Here, thegray balance guide map 56 represents designators of a plurality ofchroma components in different locations on a two-dimensional space. Forexample, as shown in FIG. 3, designators of yellow, red, magenta, blue,cyan, and green may be expressed as “Yellow”, “Red”, “Magenta”, “Blue”,“Cyan”, and “Green”. Here, the gray balance cursors 54 and 58 arelocated in the reference patch 50 and the gray balance guide map 56,respectively, and may be manipulated by the user so as to move them thesame distance at the same time and in the same direction. For example,when the user moves the gray balance cursor 58 toward a location of thedesignator “Red”, i.e., in the left horizontal direction, with apointing device such as a mouse or the like, the gray balance cursor 54in the reference patch 50 also moves the same distance and at the timeas the gray balance cursor 58. As the gray balance cursor 58 in the graybalance guide map 56 approaches an arbitrary designator, a chromacomponent designated by the arbitrary designator may be graduallyremoved from the reference patch 50. Alternatively, as the gray balancecursor 58 in the gray balance guide map 56 becomes farther from thearbitrary designator, the chroma component designated by the arbitrarydesignator may be gradually removed from the reference patch 50.

For example, when the reference patch 50 includes an R component as anon-gray component, the user moves the gray balance cursor 58 in theleft horizontal direction toward the designator “Red” until the Rcomponent is removed from the reference patch 50. As the gray balancecursor 58 gets closer to “Red”, a larger amount of non-gray component,i.e., the R component, is removed from the reference patch 50. Here, theuser determines the distance to move the gray balance cursor 58 toward adesignator, according to the characteristics of the user's visualsystem.

The luminance manipulating portion 64 of FIG. 3 corresponds to theluminance manipulator 34 of FIG. 2. For example, the reference patch 50may become dark or bright according to the left or right movement of theslide bar 66 of the luminance manipulating portion 64. Thus, the usercan move the slide bar 66 horizontally, by manipulating the pointingdevice, to match the luminance of the reference patch 50 with theluminance of the background 52.

In FIG. 3, when the user selects one of the reference patches 80 through92 of the group of reference patches 60, e.g., by manipulating thepointing device, the reference patch 50 is displayed with the sameluminance as the selected reference patch. For example, when the userselects the reference patch 88 from the group of reference patches 60,the reference patch 50 is displayed with the same luminance as thereference patch 88. As described above, the adjustment of the luminancecharacteristics of the reference patch, through the manipulation of theslide bar 66, and the removal of the non-gray components from thereference patch, through the manipulation of the gray balance cursor 58,results in adjusted reference patches for respective reference patchesof the group of reference patches 60. In other words, respectiveadjusted reference patches of the group of adjusted reference patches 62are obtained by adjusting the luminance of the reference patch 50 usingthe luminance manipulating portion 64 and removing the non-graycomponent from the reference patch 50 using the gray balance cursor 58.For example, when the reference patch 88 is selected to display thereference patch 50, as shown in FIG. 3, the luminance of the referencepatch 50 can be adjusted by the luminance manipulator 32, and/or thenon-gray component can be removed from the reference patch 50 by thechroma component manipulator 34, thereby generating the adjustedreference patch 108.

According to embodiments of the present invention, the user interface 10of FIG. 3 does not need to include the group of reference patches 60and/or the group of adjusted reference patches 62.

Also, the user interface 10 is not limited to the embodiment shown in ofFIG. 3. For example, the reference patch 50, the gray balance cursors 54and 58, the group of reference patches 60, the group of adjustedreference patches 62, the slide bar 66, and/or the gray balance guidemap 56 may have various shapes and patterns, and implemented indifferent manners.

According to embodiments of the present invention, a pattern of the graybalance cursor 54 in the reference patch 50 may be identical to apattern of the background 52 so that the user can more exactly removethe non-gray component from the reference patch 50.

Moreover, according to embodiments of the present invention, respectivebackgrounds, which are displayed paired with respective referencepatches, by the user interface 10 of FIG. 1, may have a pattern in whichat least two of black, white, and gray lines alternate each other. Here,it has been found through experimentation that for lines in thebackgrounds adjacent lines in the corresponding reference patches of thesame color should be less than “3” lines. This is because it has beenfound that it is difficult to match a luminance of a reference patchwith the luminance of a background, as processed by a user's visualsystem, when more than or equal to three lines of the same color areadjacent to one another.

FIG. 4, in illustrations (a) through (e), sets forth examples ofbackgrounds. Here, reference numbers 130 and 150 denote first and secondgray lines, respectively.

When the maximum luminance an image display device can represent is“100”, as used in Table 1, luminances of backgrounds may vary dependingon the kind and number of lines included in the backgrounds, i.e., therates of black, gray, and white lines.

TABLE 1 Background Classification Luminance (%) Background Pattern FirstBackground 11.1 Black Line (2), First Gray Line (1) Second Background33.3 Black Line (2), White Line (1) Third Background 50.0 Black Line(1), White Line (1) Fourth Background 66.7 Black Line (1), White Line(2) Fifth Background 88.9 Second Gray Line (1), White Line (2)

As shown in Table 1, each of the numbers in the parentheses in thecolumn of “Background Pattern” indicate the number of adjacent lines ineach background. In this example, first, second, third, fourth, andfifth backgrounds correspond to backgrounds shown in illustrations(a)-(e), of FIG. 4, respectively.

Here, the first gray lines 130 shown in illustration (a) have the samecolor component values as color component values of the adjustedreference patch of the reference patch displayed together with thebackground shown in illustration (b). Accordingly, an adjusted referencepatch for the reference patch displayed along with the background ofillustration (b) must be obtained prior to the adjusted reference patchof the reference patch displayed together with the background ofillustration (a). The dependency of the color component value of thefirst gray lines 130, included in the background of illustration (a), onthe adjusted reference patch of the reference patches displayed with thebackground of illustration (b) leads to the number of adjacent blacklines of illustration (b) being equal to the number of adjacent blacklines of illustration (a) and the number of lines between the blacklines of illustration (a) being equal to the number of lines between theblack lines of illustration (b).

In illustration (e), the second gray lines 150 have the same colorcomponent values as the adjusted reference patch of the reference patchdisplayed with a background of illustration (d). For this purpose, theadjusted reference patch, of the reference patch displayed together withthe background of illustration (d), must be obtained prior to theadjusted reference patch for the reference patch displayed along with abackground of illustration (e). The dependency of the color componentvalue of the second gray lines 150, included in the background ofillustration (e), on the adjusted reference patch of the reference patchdisplayed together with the background of illustration (d), leads to thenumber of adjacent white lines of illustration (e) being equal to thenumber of adjacent white lines of illustration (d) and the number oflines between white lines of illustration (e) being equal to the numberof lines between white lines of illustration (d).

FIG. 5 is a block diagram of a table generator 12 for FIG. 1, accordingto an embodiment of the present invention. Referring to FIG. 5, a tablegenerator 12A includes a gamma matcher 170 and a color component matcher172.

The gamma matcher 170 matches a luminance of each of N backgrounds,which are input from the user interface 10 via an input node IN2, withcolor component values an image may have, using a gamma function, andoutputs the matching results to the color component matcher 172.

For example, luminance Y of each of the N backgrounds may match with acolor component value V an image may have, using a gamma function, asfollows in Equation 2:

$\begin{matrix}{{Y = \left( \frac{V}{B} \right)^{\gamma}},} & (2)\end{matrix}$

wherein Y may be normalized as “1,” representing white, or as “0,”representing black, and γ denotes the gamma which may be set to “2.2” onstandard RGB (sRGB) color space, for example.

The component matcher 172 analyzes the matching results input from thegamma matcher 170, matches the color component values the image maycurrently have with the color component values of the adjusted referencepatch, input from the user interface 10 via an input node IN3, andoutputs the matching results as at least one look-up table (LUT) via anoutput node OUT3.

In this example of the comprehension of the table generator 12A of FIG.5, it is assumed that N=7, the gamma function is represented as inEquation 2, gamma is set to “2.2”, and B=255. In this case, Table 2 maybe referred to, to generate LUTs.

TABLE 2 Background Classification Luminance V R′ G′ B′ Zero^(th)Background 0 0  0  0  0 First Background 0.111 94 R1 G1 B1 SecondBackground 0.334 155 R2 G2 B2 Third Background 0.505 187 R3 G3 B3 FourthBackground 0.666 212 R4 G4 B4 Fifth Background 0.891 242 R5 G5 B5 SixthBackground 1 255 255 255 255

It is assumed that in Table 2, R, G, and B color component values V ofan image may be the same, and R′, G′, and B′ denote R, G, and B colorcomponent values of an adjusted reference patch, respectively. Forexample, (R′, G′, B′) equaling (0, 0, 0) denotes color component valuesof a zeroth adjusted reference patch, generated for a zeroth referencepatch, paired with a zeroth background, (R′, G′, B′) equaling (R1, G1,B1) denotes color component values of a first adjusted reference patchgenerated for a first reference patch paired with a first background,(R′, G′, B′) equaling (R2, G2, B2) denotes color component values of asecond adjusted reference patch generated for a second reference patchpaired with a second background, (R′, G′, B′) equaling (R3, G3, B3)denotes color component values of a third adjusted reference patchgenerated for a third reference patch paired with a third background,(R′, G′, B′) equaling (R4, G4, B4) denotes color component values of afourth adjusted reference patch generated for a fourth reference patchpaired with a fourth background, (R′, G′, B′) equaling (R5, G5, B5)denotes color component values of a fifth adjusted reference patchgenerated for a fifth reference patch paired with a fifth background,and (R′, G′, B′) equaling (255, 255, 255) denotes color component valuesof a sixth adjusted reference patch generated for a sixth referencepatch paired with a sixth background.

The gamma matcher 170 of FIG. 5 substitutes results of the gammafunction, as in Equation 2, for luminances of seven backgrounds, i.e.,zeroth through sixth backgrounds, to calculate color component values V,as shown in Table 2. In other words, the gamma matcher 170 matchesluminances of backgrounds with color component values V using a gammafunction as shown in Table 2.

Here, seven reference patches, i.e., the zeroth through sixth referencespatches, are predetermined to be paired with seven backgrounds, i.e.,the zeroth through sixth backgrounds, respectively. Therefore, the colorcomponent matcher 172 may match color component values R′, G′, and B′ ofthe adjusted reference patches, which may have been obtained for therespective reference patches through the user interface 10, with therespective color component values V, using the relationship between theluminances of the backgrounds and the color component values V, and withthe relationship being the matching result of the gamma matcher 170.

For example, the color component matcher 172 may receive a firstadjusted reference patch for a first reference patch paired with a firstbackground, as adjusted through the user interface 10. Here, the colorcomponent matcher 172 extracts color component values R1, G1, and B1 ofthe first adjusted reference patch, matches the extracted colorcomponent values R1, G1, and B1 with color component value “94” matchedwith the first background by the gamma matcher 170, and generates an LUTwhich has the color component value “94,” as an address, storing theextracted color component values R1, G1, and B1 as data. Using such amethod, as shown in Table 2, color component values V may be matchedwith color component values R′, G′, and B′ of the zeroth through sixthadjusted reference patches. For example, a first LUT can be generatedusing the relationship between the color component values V and thecolor component values R′ as shown in Table 2. A second LUT can begenerated using the relationship between the color component values Vand the color component values G′ as shown in Table 2. A third LUT canbe generated using the relationship between the color component values Vand the color component values B′ as shown in Table 2. Accordingly, thecolor component matcher 172 can generate the first, second, and thirdLUTs and outputs the first, second, and third LUTs to the colorcorrector 14.

FIG. 6 is a block diagram of the color corrector 14, according to anembodiment of the present invention. Referring to FIG. 6, a colorcorrector 14A can include a table reader 190 and a data generator 192.

The table reader 190 receives at least one LUT from the table generator12, via an input node IN4, addresses the at least one LUT using thecolor component values of an image to be displayed, input as theaddresses via an input node IN5, to read data corresponding to the colorcomponent values of the image, and outputs the read data as the resultof the correcting of the color components of the image to be displayedvia an output node OUT4.

Here, when the at least one LUT does not include data corresponding tothe color component values of the image to be displayed, input via theinput node IN5, the data generator 192 can predict data corresponding tothe color components values of the image using piecewise linear modelingand output the prediction results as the result of the correcting of thecolor of the image via an output node OUT5.

According to an embodiment of the present invention, the data generator192 may look up the at least one LUT, input via the input node IN4, todetermine that the at least one LUT does not include data correspondingto the color component values of the image to be displayed. According toan embodiment of the present invention, the data generator 192 maydetermine that the at least one LUT does not include the datacorresponding to the color components values of the image to bedisplayed, in response to a storage determination signal input from thetable reader 190. For this purpose, the table reader 190 may output tothe data generator 192 the storage determination signal indicating thatthe at least one LUT does not include data corresponding to the colorcomponents values of the image input via the input node IN5.

For an exemplary comprehension of the color corrector 14A of FIG. 6, itwill be supposed in this example that at least one LUT is generatedbased on Table 2. For example, when color component values, [V(R, G,B)=(94, 94, 94)], of an image are input to an LUT, color componentvalues R1, G1, and B1 can be output as corrected color for the colorcomponent values [V(R, G, B)=(94, 94, 94)] from the LUT.

FIG. 7 is an exemplary graph for a first LUT. Referring to FIG. 7, thehorizontal axis denotes R component values V a current image may have,and the vertical axis denotes R component value R′ of an adjustedreference patch. In other words, the horizontal axis corresponds toaddresses of the first LUT, and the vertical axis corresponds to datastored in the first LUT for correcting the current image.

The data generator 192 may obtain such a graph using the first LUT inputvia the input node IN4. In other words, the data generator 192 maydetermine the relationship between the color component values V and R′stored in the first LUT, illustrated in the graph of FIG. 7, at points210, 212, 214, 216, 218, and 220, and then the generator 192 mayextrapolate the points, or links between points, 210, 212, 214, 216,218, and 220 with straight line(s). Here, regarding FIG. 7, therepresentation of an LUT on a graph and the linking of values which maybe derived based on the LUT with straight lines refers to a piecewiselinear modeling, for example.

When the LUT does not store data corresponding to a color componentvalue of an image input via the input node IN5, i.e., the colorcomponent value V of the image is not included in the color componentvalues shown in Table 2, the data generator 192 may predict data R′corresponding to the corrected color for the color component value V ofthe image with reference to the graph of FIG. 7. For example, in a casewhere V=170, since the first LUT does not store data R′ corresponding toV=170, data R2′ on the graph of FIG. 7 can be predicted as datacorresponding to V=170. Here, the data generator 192 can then output thepredicted data R2′ as the correction result of V=170 via the output nodeOUT5.

A method of correcting the color of an image, according to an embodimentof present invention, will now be further explained with reference tothe attached drawings.

FIG. 8 is a flowchart explaining a method of correcting the color of animage, according to an embodiment of the present invention. The methodincludes operations 300 and 302 of obtaining at least one LUT usingadjusted reference patches, obtained according to characteristics of auser's visual system, and operation 304 of correcting color of an imageusing the at least one LUT.

The method of FIG. 8 may be implemented through the apparatus of FIG. 1,for example. In other words, operations 300, 302, and 304 may beperformed by the user interface 10, the table generator 12, and thecolor corrector 14, respectively.

According to an embodiment of the present invention, in operation 300,each of N reference patches can be displayed, non-gray components can beremoved from the displayed N reference patches, according tocharacteristics of the user's visual system, and the reference patchesfrom which the non-gray components have been removed become adjustedreference patches.

According to another embodiment of the present invention, in operation300, a plurality of paired reference patches and backgrounds aredisplayed, pair by pair, non-gray components can be removed from thedisplayed reference patches, according to the characteristics of auser's visual system, luminances of the displayed reference patches canbe matched with luminances of the displayed backgrounds, according tothe characteristics of the user's visual system, and the referencepatches, from which the non-gray components have been removed andluminances of which have been matched with the luminances of thedisplayed backgrounds, become the adjusted reference patches.

After operation 300, in operation 302, at least one LUT can begenerated, with the LUT having color component values of an image asaddresses and include color component values of the adjusted referencepatches as data.

After operation 302, in operation 304, at least one LUT is addressedusing the color component values of the image, to read datacorresponding to the color component values of the image, and the readdata can result in the correcting of the color of the image.

FIG. 9 is a flowchart for explaining an embodiment 300A of operation 300of FIG. 8. Operation 300A includes operations 400, 402, 404, 406, 408,and 410 of obtaining adjusted reference patches for reference patches.

According to an embodiment of the present invention, in operation 400, avariable n is initialized to, for example, “1”. After operation 400, inoperation 402, a paired nth reference patch and nth background isdisplayed. After operation 402, in operation 404, a luminance of the nthreference patch is matched with a luminance of the nth background,according to the characteristics of the user's visual system, and anadjusted reference patch is generated based on the matching result. Forexample, a user may determine, according to the characteristics of theuser's visual system, whether the luminance of the nth reference patchseems identical to the luminance of the nth background. If the userdetermines that the luminance of the nth reference patch does not seemidentical to the luminance of the nth background, the user may thenadjust the luminance of the nth reference patch so as to match with theluminance of the nth background.

After operation 404, in operation 406, a non-gray component may beremoved from the displayed nth reference patch, according to thecharacteristics of the user's visual system, and an adjusted referencepatch may be generated based on the removal result. For example, theuser may determine, according to the characteristics of the user'svisual system, whether the displayed nth reference patch includes thenon-gray component. If the user determines that the displayed nthreference patch includes the non-gray component, the user may remove thenon-gray component from the nth reference patch up to until the non-graycomponent is completely removed from the nth reference patch. Afteroperation 406, in operation 408, a determination can be made as towhether the variable n is equal to N. In other words, a determinationcan be made as to whether operations 404 and 406 have been completelyperformed on all of reference patches.

If in operation 408, it is determined that the variable n is equal to N,the process moves on to operation 302 to generate an LUT. If inoperation 408, it is determined that the variable n is not equal to N,in operation 410, the variable n increases by “1” and the processreturns to operation 402 for the next reference patch.

According to another embodiment of the present invention, operation 300Aof FIG. 9 may not include operation 404. In this case, operation 406 maybe performed after operation 402.

According to yet another embodiment of the present invention, operation404 of FIG. 9 may be performed not between operations 402 and 406 butbetween operations 406 and 408. In this case, operation 406 can beperformed after operation 402, operation 404 can be performed afteroperation 406, and operation 408 can be performed after operation 404.

Embodiments of the present invention may be implemented through computerreadable code/instructions embodied in a medium, e.g., acomputer-readable medium, including but not limited to storage mediasuch as magnetic storage media (ROMs, RAMs, floppy disks, magnetictapes, etc.), and optically readable media (CD-ROMs, DVDs, etc.). Thefunctional programs, instructions, codes and code segments forimplementing the present invention may be easily deducted by programmersin the art which the present invention belongs to after review of thepresent disclosure.

The above-described image color-correcting apparatus, medium, andmethod, according to embodiments of the present invention, can beadopted to edit an image displayed on an image display device.

As described above, in an apparatus, medium, and method for correctingthe color of an image, luminance characteristics of an image displaydevice can be corrected according to the characteristics of a user'svisual system, without using a high-priced colorimetric apparatus. Also,non-gray components, which may be generated during the reproduction of ablack and white image, can be removed. For example, with a userinterface screen as shown in FIG. 3, a user can relatively easily adjusta reference patch, according to the characteristics of the user's visualsystem. As a result, the user can conveniently correct the color of animage to be displayed.

Although a few embodiments of the present invention have been shown anddescribed, it would be appreciated by those skilled in the art thatchanges may be made in these embodiments without departing from theprinciples and spirit of the invention, the scope of which is defined inthe claims and their equivalents.

1. An apparatus for correcting color of an image, the apparatuscomprising: a user interface to display each of N reference patches,with N being a number greater than or equal to 1, to remove a non-graycomponent from a displayed selected reference patch, of the N referencepatches, selectively overlaid on a displayed corresponding background,based on user interaction and according to characteristics of a user'svisual system, as an adjusted reference patch, and to output theadjusted reference patch, wherein the user interface includes a userpatch manipulator to be manipulated by the user to control displaycharacteristics of the selected reference patch, overlaying thedisplayed corresponding background, with the user patch manipulatorbeing displayed as an overlay within the displayed selected referencepatch; a table generator to generate at least one table comprising colorcomponent values, as addresses, and storing color component values ofthe adjusted reference patch as data in the at least one table; and acolor corrector to address the at least one table, using color componentvalues of the image, to read data corresponding to the color componentvalues of the image and output the read data for a color correctedimage, wherein the user interface displays a plurality of pairedreference patches and backgrounds, pair by pair, removes non-graycomponents from the displayed reference patches, according to thecharacteristics of the user's visual system, matches luminances of thedisplayed reference patches with luminances of displayed backgrounds,according to the characteristics of the user's visual system, asadjusted references patches, respectively, and outputs the adjustedreference patches, wherein each of the plurality of pairs includes onepredetermined reference patch paired with one predetermined background.2. The apparatus of claim 1, wherein the user interface comprises: aluminance manipulator to be manipulated by the user to match a luminanceof the displayed reference patch with a luminance of a paired displayedbackground, as the overlaid corresponding background; a color componentmanipulator to be manipulated by the user to remove the non-graycomponent from the displayed reference patch; and an adjusted referencepatch generator to generate the adjusted reference patch for thedisplayed reference patch based on the luminance manipulation and thecolor component manipulation.
 3. The apparatus of claim 2, wherein thecolor component manipulator comprises: a gray balance guide map torepresent designators of a plurality of chroma components in differentlocations on a two-dimensional space; and gray balance cursors providedwithin the displayed reference patch, as the user patch manipulator, andthe gray balance guide map and to be manipulated by the user so as tomove the gray balance cursors together an identical distance in anidentical direction, wherein, as a gray balance cursor within the graybalance guide map gets closer to an arbitrary designator, a chromacomponent associated with the arbitrary designator is correspondinglyremoved from the displayed reference patch.
 4. The apparatus of claim 3,wherein a pattern of the gray balance cursors within the displayedreference patch is identical to a pattern of the displayed background.5. The apparatus of claim 1, wherein the displayed background has apattern in which at least two of black, white, and gray lines alternateeach other.
 6. The apparatus of claim 5, wherein in the displayedbackground, a number of adjacent lines with a same color are less than 3lines.
 7. The apparatus of claim 1, wherein the table generatorcomprises: a gamma matcher to match the luminances of N backgrounds,with color component values the image may have, using a gamma function;and a color component matcher to analyze the gamma matcher matchingresults, match the color components values the image may have with thecolor component values of the adjusted reference patches, and output thecolor component value matching results as at least one table.
 8. Theapparatus of claim 1, wherein the color corrector comprises: a tablereader to address the at least one table, using the color componentvalues of the image, to read the data corresponding to the colorcomponent values of the image and output the read data for the colorcorrected image; and a data generator to, when the at least one tabledoes not include data corresponding to the color component values of theimage, predict data corresponding to the color component values usingpiecewise linear modeling using data from the at least one table, andoutput results of the prediction for the color corrected image.
 9. Theapparatus of claim 1, wherein the user interface further comprises twogray balance cursors respectively provided within the displayedreference patch, as the user patch manipulator, and a gray balance guidemap and to be manipulated by the user so as to move the gray balancecursors together an identical distance in an identical directionrelative to respective colors mapped in the gray balance guide map. 10.An apparatus for correcting color of an image, the apparatus comprising:a user interface to display each of N reference patches, with N being anumber greater than or equal to 1, to remove a non-gray component from adisplayed reference patch based on user interaction and according tocharacteristics of a user's visual system, as an adjusted referencepatch, and to output the adjusted reference patch; a table generator togenerate at least one table comprising color component values, asaddresses, and storing color component values of the adjusted referencepatch as data in the at least one table; and a color corrector toaddress the at least one table, using color component values of theimage, to read data corresponding to the color component values of theimage and output the read data for a color corrected image, wherein theuser interface comprises: a luminance manipulator to be manipulated bythe user to match a luminance of the displayed reference patch with aluminance of a paired displayed background; a color componentmanipulator to be manipulated by the user to remove the non-graycomponent from the displayed reference patch; and an adjusted referencepatch generator to generate the adjusted reference patch for thedisplayed reference patch based on the luminance manipulation and thecolor component manipulation, wherein the color component manipulatorcomprises: a gray balance guide map to represent designators of aplurality of chroma components in different locations on atwo-dimensional space; and gray balance cursors provided within thedisplayed reference patch and the gray balance guide map and to bemanipulated by the user so as to move the gray balance cursors togetheran identical distance in an identical direction, wherein, as a graybalance cursor within the gray balance guide map gets closer to anarbitrary designator, a chroma component associated with the arbitrarydesignator is correspondingly removed from the displayed referencepatch.
 11. The apparatus of claim 10, wherein a pattern of the graybalance cursors within the reference patch is identical to a pattern ofthe displayed background.
 12. A method of correcting color of an image,the method comprising: displaying each of N, with N being a numbergreater than or equal to 1, reference patches selectively overlaid onrespective displayed corresponding backgrounds, removing a non-graycomponent from a selected reference patch, of the N reference patches,according to an interaction by a user and characteristics of a user'svisual system, and determining the non-gray component removed referencepatch as an adjusted reference patch, wherein the user interactionincludes interacting with a user patch manipulator to control displaycharacteristics of the selected reference patch, overlaying a displayedcorresponding background, with the user patch manipulator beingdisplayed as an overlay within the displayed selected reference patch;generating at least one table that has, as addresses, color componentvalues and stores color component values of the adjusted reference patchas data in the at least one table; and addressing the at least onetable, using color component values of the image, to read datacorresponding to the color component values of the image and outputtingthe read data for a color corrected image, wherein a plurality of pairsof reference patches and backgrounds are displayed, pair by pair,non-gray components are removed from the displayed reference patches,according to the characteristics of the user's visual system, luminancesof the displayed reference patches match with luminances of thedisplayed backgrounds, according to the characteristics of the user'svisual system, as the adjusted reference patches, wherein each of theplurality of pairs includes one predetermined reference patch pairedwith one predetermined background.
 13. The method of claim 12, whereinthe outputting of the adjusted reference patches comprises: initializinga variable n; displaying a paired nth reference patch and an nthbackground, together; removing a non-gray component from the displayednth reference patch, according to the characteristics of the user'svisual system; determining whether the variable n is equal to N and ifit is determined that the variable n is equal to N proceeding to thegenerating of the at least lookup table, and if it is determined thatthe variable n is not equal to N increasing the variable n by 1 andproceeding to the displaying of the nth reference patch and the nthbackground.
 14. The method of claim 13, where the outputting of theadjusted reference patches further comprises: matching a luminance ofthe nth reference patch with a luminance of the nth background,according to the characteristics of the user's visual system.
 15. Atleast one computer readable medium structure comprising computerreadable code to control an implementation of the method of claim 12.16. An apparatus for correcting color of an image, the apparatuscomprising: a user interface to display each of N reference patches,with N being a number greater than 1, with a user selected referencepatch of the N reference patches being displayed together with all Nreference patches and concurrently with a separate display of the userselected reference patch overlaid on a corresponding background, toremove a non-gray component from the selected reference patch overlaidon the corresponding background based on user interaction and accordingto characteristics of a user's visual system, as an adjusted referencepatch, and to output the adjusted reference patch; a table generator togenerate at least one table comprising color component values, asaddresses, and storing color component values of the adjusted referencepatch as data in the at least one table; and a color corrector toaddress the at least one table, using color component values of theimage, to read data corresponding to the color component values of theimage and output the read data for a color corrected image, wherein theuser interface displays a plurality of paired reference patches andbackgrounds, pair by pair, removes non-gray components from thedisplayed reference patches, according to the characteristics of theuser's visual system, matches luminances of the displayed referencepatches with luminances of displayed backgrounds, according to thecharacteristics of the user's visual system, as adjusted referencespatches, respectively, and outputs the adjusted reference patches,wherein each of the plurality of pairs includes one predeterminedreference patch paired with one predetermined background.
 17. Theapparatus of claim 16, wherein the color component manipulatorcomprises: a gray balance guide map to represent designators of aplurality of chroma components in different locations on atwo-dimensional space; and gray balance cursors provided within thedisplayed reference patch and the gray balance guide map and to bemanipulated by the user so as to move the gray balance cursors togetheran identical distance in an identical direction, wherein, as a graybalance cursor within the gray balance guide map gets closer to anarbitrary designator, a chroma component associated with the arbitrarydesignator is correspondingly removed from the displayed referencepatch.
 18. The apparatus of claim 17, wherein a pattern of the graybalance cursors within the reference patch is identical to a pattern ofthe displayed background.
 19. The apparatus of claim 16, wherein theuser interface comprises: a luminance manipulator to be manipulated bythe user to match a luminance of the displayed reference patch with aluminance of a paired displayed background, as the correspondingoverlaid background; a color component manipulator to be manipulated bythe user to remove the non-gray component from the displayed referencepatch; and an adjusted reference patch generator to generate theadjusted reference patch for the displayed reference patch based on theluminance manipulation and the color component manipulation.
 20. Theapparatus of claim 19, wherein the color component manipulatorcomprises: a gray balance guide map to represent designators of aplurality of chroma components in different locations on atwo-dimensional space; and gray balance cursors provided within thedisplayed reference patch and the gray balance guide map and to bemanipulated by the user so as to move the gray balance cursors togetheran identical distance in an identical direction, wherein, as a graybalance cursor within the gray balance guide map gets closer to anarbitrary designator, a chroma component associated with the arbitrarydesignator is correspondingly removed from the displayed referencepatch.
 21. The apparatus of claim 16, wherein the table generatorcomprises: a gamma matcher to match the luminances of N backgrounds,with color component values the image may have, using a gamma function;and a color component matcher to analyze the gamma matcher matchingresults, match the color components values the image may have with thecolor component values of the adjusted reference patches, and output thecolor component value matching results as at least one table.
 22. Theapparatus of claim 16, wherein the color corrector comprises: a tablereader to address the at least one table, using the color componentvalues of the image, to read the data corresponding to the colorcomponent values of the image and output the read data for the colorcorrected image; and a data generator to, when the at least one tabledoes not include data corresponding to the color component values of theimage, predict data corresponding to the color component values usingpiecewise linear modeling using data from the at least one table, andoutput results of the prediction for the color corrected image.
 23. Theapparatus of claim 16, wherein the user interface further comprises twogray balance cursors respectively provided within the displayedreference patch and a gray balance guide map and to be manipulated bythe user so as to move the gray balance cursors together an identicaldistance in an identical direction relative to respective colors mappedin the gray balance guide map.
 24. A method of correcting color of animage, the method comprising: displaying each of N reference patches,with N being a number greater than 1, with a user selected referencepatch of the N reference patches being displayed together with all Nreference patches and concurrently with a separate display of the userselected reference patch overlaid on a corresponding background,removing a non-gray component from the selected reference patch,according to an interaction by a user and characteristics of a user'svisual system, and determining the non-gray component removed referencepatch as an adjusted reference patch; generating at least one table thathas, as addresses, color component values and stores color componentvalues of the adjusted reference patch as data in the at least onetable; and addressing the at least one table, using color componentvalues of the image, to read data corresponding to the color componentvalues of the image and outputting the read data for a color correctedimage, wherein a plurality of pairs of reference patches and backgroundsare displayed, pair by pair, non-gray components are removed from thedisplayed reference patches, according to the characteristics of theuser's visual system, luminances of the displayed reference patchesmatch with luminances of the displayed backgrounds, according to thecharacteristics of the user's visual system, as the adjusted referencepatches, wherein each of the plurality of pairs includes onepredetermined reference patch paired with one predetermined background.25. The method of claim 24, wherein the outputting of the adjustedreference patches comprises: initializing a variable n; displaying apaired nth reference patch and an nth background, together; removing anon-gray component from the displayed nth reference patch, according tothe characteristics of the user's visual system; determining whether thevariable n is equal to N and if it is determined that the variable n isequal to N proceeding to the generating of the at least lookup table,and if it is determined that the variable n is not equal to N increasingthe variable n by 1 and proceeding to the displaying of the nthreference patch and the nth background.
 26. The method of claim 25,where the outputting of the adjusted reference patches furthercomprises: matching a luminance of the nth reference patch with aluminance of the nth background, according to the characteristics of theuser's visual system.
 27. At least one computer readable mediumstructure comprising computer readable code to control an implementationof the method of claim 24.